You may add the following options to dictate who says the magic word, and when.
notme, me, now or a combination "notmenow" "menow"
E.g. Task leader targets Gribble Grobblenobber or enters in quotes "Gribble Grobblenobber"
/mac ready leave - The group moseys to the task giver, and when the instance is ready, says leave
/mac ready leave "Gribble Grobblenobber" now - Everyone immediately runs to Gribble Grobblenobber and says leave
/mac ready leave me - Only the task leader says leave, assuming the task giver is targetted
/mac ready leave notme - Everyone but the task leader...
/mac ready leave notmenow - Everyone but the task leader get to the task giver and say leave without waiting.